CameraService: Add support for YCrCb_420_SP overlay format

This patch adds support for YCrCb_420_SP as the preview format,
it works exactly the same as the YCbCr_420_SP toggle and does
not change the behaviour unless toggled by the following board
config:

BOARD_OVERLAY_FORMAT_YCrCb_420_SP := true
- Uses YCrCb_420_SP as the overlay format for the preview display.

Change-Id: I3a98ff28fc79696a52b98ec6dc452950e3f0c7bf